1. Field of the Invention
The present invention relates to a method for processing video, and relates more specifically to a method for compressing and expanding the playback time of digitized video.
2. Description of the Background Art
Nonlinear editing systems are widely used today by, for example, broadcasting studios and video production companies. Nonlinear editing systems capture digitized video to a computer so that the video can be processed in memory, and can therefore accomplish such editing tasks as scene selection and applying special effects much more quickly and easily than is possible with conventional tape-based editing systems.
There are times, however, when it is desirable to increase or decrease (expand or compress) the playback time of the edited video when video edited on a nonlinear editing system is reproduced. For example, late-breaking news may cause a disruption in the broadcasting schedule in which the edited video is to be broadcast, and the available broadcasting time may change. This change can be eliminated or absorbed, however, by compressing or expanding the playback time of the edited video.
The playback time of edited video has conventionally been compressed or expanded by either changing the playback speed, or by re-editing the edited video to delete part of the video or add another part as necessary.
When the former method is used to increase or decrease the playback time of the edited video, however, image motions become slower and the associated audio drops in pitch, or motions become faster and the audio rises in pitch. In either case, the video and audio appear unnatural to the viewer. Using the latter method to re-edit the edited video, however, increases the work load on the operator and takes additional editing time.
Therefore, an object of the present invention is to provide a playback time compression and expansion method and apparatus whereby the playback time of digitized video can be increased or decreased easily and in a short period of time without the viewer perceiving unnatural video or audio.
The present invention has the following features to achieve the object above.
A first aspect of the present invention is directed to a playback time expansion method for lengthening a playback time of digitized video, comprising:
a step for measuring a rate of video change for all frames in the digitized video,
the rate of video change indicating how much video in a particular frame has changed compared with video in a frame before and a frame after;
a step for recording the video;
a step for calculating a number of manipulation frames based on a playback time before the video playback time expansion and a playback time after the video playback time expansion,
the number of manipulation frames indicating a number of frames to be manipulated in the total number of frames in the video;
a step for selecting a number of frames equal to the number of manipulation frames from among all frames in the video in sequence from the lowest rate of video change; and
a step for outputting recorded video;
wherein the step for outputting recorded video is characterized by manipulating the selected frames such that the video of each selected frame is output a plurality of times.
By thus outputting the video of frames having a low rate of video change a plurality of times to increase the playback time, a playback time expansion method as set forth in the first aspect of the invention can increase the playback time easily and in a short time compared with methods in which the playback time is increased by re-editing. In addition, the viewer also perceives less unnatural video compared with methods in which the playback time is increased by varying the playback speed because there is no slowing of image motion.
A second aspect of the present invention is directed to a playback time expansion method as set forth in the first aspect of the invention, wherein digitized audio is associated with the video, the method further comprises:
a step for measuring an audio level for every frame in the video, and
the step for frame selection is characterized by selecting frames with priority for frames in which the audio level is below a predetermined level.
By thus outputting the video of frames having a low rate of video change and a low audio level a plurality of times to increase the playback time, a playback time expansion method as set forth in the second aspect of the invention can increase the playback time easily and in a short time compared with methods in which the playback time is increased by re-editing. In addition, the viewer also perceives less unnatural video and audio compared with methods in which the playback time is increased by varying the playback speed because there is no slowing of image motion and lowering of audio pitch.
A third aspect of the present invention is directed to a playback time expansion method as set forth in the first aspect of the invention, further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block.
By thus dispersing the manipulated frames through a wider range, a playback time expansion method as set forth in the third aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A fourth aspect of the present invention is directed to a playback time expansion method as set forth in the first aspect of the invention, further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block and any block adjacent thereto.
By thus dispersing the manipulated frames through an even wider range, a playback time expansion method as set forth in the third aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A fifth aspect of the present invention is directed to a playback time expansion method as set forth in the first aspect of the invention, further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting frames equally from the plurality of blocks.
By thus dispersing the manipulated frames evenly throughout all frames, a playback time expansion method as set forth in the fifth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A sixth aspect of the present invention is directed to a playback time compression method for shortening a playback time of digitized video, comprising:
a step for measuring a rate of video change for all frames in the digitized video,
the rate of video change indicating how much video in a particular frame has changed compared with video in a frame before and a frame after;
a step for recording the video;
a step for calculating a number of manipulation frames based on a playback time before the video playback time compression and a playback time after the video playback time compression,
the number of manipulation frames indicating a number of frames to be manipulated in the total number of frames in the video;
a step for selecting a number of frames equal to the number of manipulation frames from among all frames in the video in sequence from the lowest rate of video change; and
a step for outputting recorded video;
wherein the step for outputting recorded video is characterized by manipulating the selected frames such that the video of each selected frame is not output.
By thus dropping the video of frames having a low rate of video change to decrease the playback time, a playback time expansion method as set forth in the sixth aspect of the invention can decrease the playback time easily and in a short time compared with methods in which the playback time is decreased by re-editing. In addition, the viewer also perceives less unnatural video compared with methods in which the playback time is decreased by varying the playback speed because there is no quickening of image motion. e
A seventh aspect of the present invention is directed to a playback time compression method as set forth in the sixth aspect of the invention, wherein digitized audio is associated with the video, the method further comprises:
a step for measuring an audio level for every frame in the video, and
the step for frame selection is characterized by selecting frames with priority for frames in which the audio level is below a predetermined level.
By thus dropping the video of frames having a low rate of video change and a low audio level to decrease the playback time, a playback time compression method as set forth in the seventh aspect of the invention can decrease the playback time easily and in a short time compared with methods in which the playback time is decreased by re-editing. In addition, the viewer also perceives less unnatural video and audio compared with methods in which the playback time is decreased by varying the playback speed because there is no quickening of image motion and increase in the audio pitch.
An eighth aspect of the present invention is directed to a playback time compression method as set forth in the sixth aspect of the invention, further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block.
By thus dispersing the manipulated frames through a wider range, a playback time expansion method as set forth in the eighth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A ninth aspect of the present invention is directed to a playback time compression method as set forth in the sixth aspect of the invention, further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block and any block adjacent thereto.
By thus dispersing the manipulated frames through an even wider range, a playback time expansion method as set forth in the ninth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A tenth aspect of the present invention is directed to a playback time compression method as set forth in the sixth aspect of the invention, further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting frames equally from the plurality of blocks.
By thus dispersing the manipulated frames evenly throughout all frames, a playback time expansion method as set forth in the tenth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
An eleventh aspect of the present invention is directed to an apparatus for lengthening a playback time of digitized video, comprising:
rate of video change measuring means for measuring a rate of video change for all frames in the digitized video,
the rate of video change indicating how much video in a particular frame has changed compared with video in a frame before and a frame after;
recording means for recording the video;
calculating means for calculating a number of manipulation frames based on a playback time before the video playback time expansion and a playback time after the video playback time expansion,
the number of manipulation frames indicating a number of frames to be manipulated in the total number of frames in the video;
frame selecting means for selecting a number of frames equal to the number of manipulation frames from among all frames in the video in sequence from the lowest rate of video change; and
output means for outputting video recorded by the recording means;
wherein the output means is characterized by manipulating the selected frames during video output such that the video of each frame selected by the frame selecting means is output a plurality of times.
By thus outputting the video of frames having a low rate of video change a plurality of times to increase the playback time, the eleventh aspect of the invention can increase the playback time easily and in a short time compared with methods in which the playback time is increased by re-editing. In addition, the viewer also perceives less unnatural video compared with methods in which the playback time is increased by varying the playback speed because there is no slowing of image motion.
A twelfth aspect of the present invention is directed to a playback time expansion apparatus as set forth in the eleventh aspect of the invention, wherein digitized audio is associated with the video, the apparatus further comprises:
audio level measuring means for measuring an audio level for every frame in the video, and
the frame selecting means is characterized by selecting frames with priority for frames in which the audio level is below a predetermined level.
By thus outputting the video of frames having a low rate of video change and a low audio level a plurality of times to increase the playback time, the twelfth aspect of the invention can increase the playback time easily and in a short time compared with methods in which the playback time is increased by re-editing. In addition, the viewer also perceives less unnatural video and audio compared with methods in which the playback time is increased by varying the playback speed because there is no slowing of image motion and lowering of audio pitch.
A thirteenth aspect of the present invention is directed to a playback time expansion apparatus as set forth in the eleventh aspect of the invention, further comprising:
means for segmenting the total number of frames in the video into a plurality of blocks;
wherein the frame selecting means is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block.
By thus dispersing the manipulated frames through a wider range, the thirteenth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A fourteenth aspect of the present invention is directed to a playback time expansion apparatus as set forth in the eleventh aspect of the invention, further comprising:
means for segmenting the total number of frames in the video into a plurality of blocks;
wherein the frame selecting means is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block and any block adjacent thereto.
By thus dispersing the manipulated frames through an even wider range, the fourteenth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A fifteenth aspect of the present invention is directed to a playback time expansion apparatus as set forth in the eleventh aspect of the invention, further comprising:
means for segmenting the total number of frames in the video into a plurality of blocks;
wherein the frame selecting means is characterized by selecting frames equally from the plurality of blocks.
By thus dispersing the manipulated frames evenly throughout all frames, the fifteenth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A sixteenth aspect of the present invention is directed to a playback time compression apparatus for shortening a playback time of digitized video, comprising:
rate of video change measuring means for measuring a rate of video change for all frames in the digitized video,
the rate of video change indicating how much video in a particular frame has changed compared with video in a frame before and a frame after;
recording means for recording the video;
calculating means for calculating a number of manipulation frames based on a playback time before the video playback time compression and a playback time after the video playback time compression,
the number of manipulation frames indicating a number of frames to be manipulated in the total number of frames in the video;
frame selecting means for selecting a number of frames equal to the number of manipulation frames from among all frames in the video in sequence from the lowest rate of video change; and
output means for outputting video recorded by the recording means;
wherein the output means is characterized by manipulating the selected frames during video output such that the video of each frame selected by the frame selecting means is not output.
By thus dropping the video of frames having a low rate of video change to decrease the playback time, the sixteenth aspect of the invention can decrease the playback time easily and in a short time compared with methods in which the playback time is decreased by re-editing. In addition, the viewer also perceives less unnatural video compared with methods in which the playback time is decreased by varying the playback speed because there is no quickening of image motion.
A seventeenth aspect of the present invention is directed to a playback time compression apparatus as set forth in the sixteenth aspect of the invention, wherein digitized audio is associated with the video, the apparatus further comprises:
audio level measuring means for measuring an audio level for every frame in the video, and
the frame selecting means is characterized by selecting frames with priority for frames in which the audio level is below a predetermined level.
By thus dropping the video of frames having a low rate of video change and a low audio level to decrease the playback time, the seventeenth aspect of the invention can decrease the playback time easily and in a short time compared with methods in which the playback time is decreased by re-editing. In addition, the viewer also perceives less unnatural video and audio compared with methods in which the playback time is decreased by varying the playback speed because there is no quickening of image motion and increase in the audio pitch.
An eighteenth aspect of the present invention is directed to a playback time compression apparatus as set forth in the sixteenth aspect of the invention, further comprising:
means for segmenting the total number of frames in the video into a plurality of blocks;
wherein the frame selecting means is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block.
By thus dispersing the manipulated frames through an even wider range, the eighteenth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A nineteenth aspect of the present invention is directed to a playback time compression apparatus as set forth in the sixteenth aspect of the invention, further comprising:
means for segmenting the total number of frames in the video into a plurality of blocks;
wherein the frame selecting means is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block and any block adjacent thereto.
By thus dispersing the manipulated frames through an even wider range, the nineteenth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A twentieth aspect of the present invention is directed to a playback time compression apparatus as set forth in the sixteenth aspect of the invention, further comprising:
means for segmenting the total number of frames in the video into a plurality of blocks;
wherein the frame selecting means is characterized by selecting frames equally from the plurality of blocks.
By thus dispersing the manipulated frames evenly throughout all frames, the twentieth aspect of the invention can prevent viewer perception of unnatural video resulting from a concentration of manipulation frames in a particular part of the video.
A twenty-first aspect of the present invention is directed to a recording medium for recording a computer executable program achieving an operating environment for lengthening a playback time of digitized video, the program comprising:
a step for measuring a rate of video change for all frames in the digitized video,
the rate of video change indicating how much video in a particular frame has changed compared with video in a frame before and a frame after;
a step for recording the video;
a step for calculating a number of manipulation frames based on a playback time before the video playback time expansion and a playback time after the video playback time expansion,
the number of manipulation frames indicating a number of frames to be manipulated in the total number of frames in the video;
a step for selecting a number of frames equal to the number of manipulation frames from among all frames in the video in sequence from the lowest rate of video change; and
a step for outputting recorded video;
wherein the step for outputting recorded video is characterized by manipulating the selected frames such that the video of each selected frame is output a plurality of times.
A twenty-second aspect of the present invention is directed to a recording medium as set forth in the twenty-first aspect of the invention for recording a computer executable program achieving an operating environment wherein digitized audio is associated with the video, and the program further comprises:
a step for measuring an audio level for every frame in the video, and
the step for frame selection is characterized by selecting frames with priority for frames in which the audio level is below a predetermined level.
A twenty-third aspect of the present invention is directed to a recording medium as set forth in the twenty-first aspect of the invention for recording a computer executable program achieving an operating environment further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block.
A twenty-fourth aspect of the present invention is directed to a recording medium as set forth in the twenty-first aspect of the invention for recording a computer executable program achieving an operating environment further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block and any block adjacent thereto.
A twenty-fifth aspect of the present invention is directed to a recording medium as set forth in the twenty-first aspect of the invention for recording a computer executable program achieving an operating environment further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting frames equally from the plurality of blocks.
A twenty-sixth aspect of the present invention is directed to a recording medium for recording a computer executable program achieving an operating environment for shortening a playback time of digitized video, the program comprising:
a step for measuring a rate of video change for all frames in the digitized video,
the rate of video change indicating how much video in a particular frame has changed compared with video in a frame before and a frame after;
a step for recording the video;
a step for calculating a number of manipulation frames based on a playback time before the video playback time compression and a playback time after the video playback time compression,
the number of manipulation frames indicating a number of frames to be manipulated in the total number of frames in the video;
a step for selecting a number of frames equal to the number of manipulation frames from among all frames in the video in sequence from the lowest rate of video change; and
a step for outputting recorded video;
wherein the step for outputting recorded video is characterized by manipulating the selected frames such that the video of each selected frame is not output.
A twenty-seventh aspect of the present invention is directed to a recording medium as set forth in the twenty-sixth aspect of the invention for recording a computer executable program achieving an operating environment wherein digitized audio is associated with the video, and the program further comprises:
a step for measuring an audio level for every frame in the video, and
the step for frame selection is characterized by selecting frames with priority for frames in which the audio level is below a predetermined level.
A twenty-eighth aspect of the present invention is directed to a recording medium as set forth in the twenty-sixth aspect of the invention for recording a computer executable program achieving an operating environment further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block.
A twenty-ninth aspect of the present invention is directed to a recording medium as set forth in the twenty-sixth aspect of the invention for recording a computer executable program achieving an operating environment further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting a frame from one of a plurality of the blocks, and then selecting a next frame from a block other than the one block and any block adjacent thereto.
A thirtieth aspect of the present invention is directed to a recording medium as set forth in the twenty-sixth aspect of the invention for recording a computer executable program achieving an operating environment further comprising:
a step for segmenting the total number of frames in the video into a plurality of blocks;
wherein the step for frame selection is characterized by selecting frames equally from the plurality of blocks.
A thirty-first aspect of the present invention is directed to a playback time expansion and compression method for lengthening or shortening a playback time of digitized video, comprising:
a step for measuring a rate of video change for all frames in the digitized video,
the rate of video change indicating how much video in a particular frame has changed compared with video in a frame before and a frame after;
a step for recording the video;
a step for determining a manipulation sequence number for every frame in the video in relation to the rate of video change,
the manipulation sequence number indicating a sequence in which the frames are to be manipulated;
a step for compiling a table recording the manipulation sequence numbers;
a step for calculating a number of manipulation frames based on a playback time before the video playback time expansion/compression and a playback time after the video playback time expansion/compression,
the number of manipulation frames indicating a number of frames to be manipulated in the total number of frames in the video;
a step for selecting, in reference to the table, a number of frames equal to the number of manipulation frames from among all frames in the video in sequence from the lowest rate of video change; and
a step for outputting recorded video;
wherein the step for outputting recorded video is characterized by manipulating the selected frames such that
when the playback time is lengthened, the video of each selected frame is output a plurality of times, and
when the playback time is shortened, the video of each selected frame is not output.
As described above, the thirty-first aspect of the present invention outputs the video of frames having a low rate of video change a plurality of times to increase the playback time, and drops the video of frames having a low rate of video change to decrease the playback time. As a result, it can increase or decrease the playback time easily and in a short time compared with methods in which the playback time is decreased by re-editing. In addition, the viewer also perceives less unnatural video compared with methods in which the playback time is decreased by varying the playback speed because image motion does not become faster or slower. Moreover, because a table containing manipulation sequence numbers is compiled and the manipulation frames are selected with reference to this table, once the table is compiled, the playback time can thereafter be easily and freely increased or decreased.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.